Some image displays include touch panels. Types of touch panels include an optical type touch panel optically detecting a finger or the like in addition to a resistance type touch panel using a change in electrical resistance and a capacitance type touch panel using a change in capacitance. For example, in the optical type touch panel, an image is displayed on a display surface thereof by modulating light from a backlight in a liquid crystal element, and light emitted from the display surface and then reflected from a proximity object such as a finger is received by photoreception elements arranged on the display surface so as to detect the position or the like of the proximity object. Patent Document 1 discloses such an image display. The display disclosed in Patent Document 1 includes a display section including a display means for displaying an image and an image-pickup means for picking up an image of an object.
When such an optical type touch panel detects a plurality of points, in some cases, a process of providing an identification number to each connected region considered as one set of points is performed on data captured as an image from photoreception elements (for example, refer to Patent Document 2). Such a process is called a labeling process.